diff options
Diffstat (limited to 'libavcodec/xfacedec.c')
| -rw-r--r-- | libavcodec/xfacedec.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/libavcodec/xfacedec.c b/libavcodec/xfacedec.c new file mode 100644 index 0000000..ab4c082 --- /dev/null +++ b/libavcodec/xfacedec.c @@ -0,0 +1,188 @@ +/* + * Copyright (c) 1990 James Ashton - Sydney University + * Copyright (c) 2012 Stefano Sabatini + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/** + * @file + * X-Face decoder, based on libcompface, by James Ashton. + */ + +#include "libavutil/pixdesc.h" +#include "avcodec.h" +#include "bytestream.h" +#include "internal.h" +#include "xface.h" + +static int pop_integer(BigInt *b, const ProbRange *pranges) +{ + uint8_t r; + int i; + + /* extract the last byte into r, and shift right b by 8 bits */ + ff_big_div(b, 0, &r); + + i = 0; + while (r < pranges->offset || r >= pranges->range + pranges->offset) { + pranges++; + i++; + } + ff_big_mul(b, pranges->range); + ff_big_add(b, r - pranges->offset); + return i; +} + +static void pop_greys(BigInt *b, char *bitmap, int w, int h) +{ + if (w > 3) { + w /= 2; + h /= 2; + pop_greys(b, bitmap, w, h); + pop_greys(b, bitmap + w, w, h); + pop_greys(b, bitmap + XFACE_WIDTH * h, w, h); + pop_greys(b, bitmap + XFACE_WIDTH * h + w, w, h); + } else { + w = pop_integer(b, ff_xface_probranges_2x2); + if (w & 1) bitmap[0] = 1; + if (w & 2) bitmap[1] = 1; + if (w & 4) bitmap[XFACE_WIDTH] = 1; + if (w & 8) bitmap[XFACE_WIDTH + 1] = 1; + } +} + +static void decode_block(BigInt *b, char *bitmap, int w, int h, int level) +{ + switch (pop_integer(b, &ff_xface_probranges_per_level[level][0])) { + case XFACE_COLOR_WHITE: + return; + case XFACE_COLOR_BLACK: + pop_greys(b, bitmap, w, h); + return; + default: + w /= 2; + h /= 2; + level++; + decode_block(b, bitmap, w, h, level); + decode_block(b, bitmap + w, w, h, level); + decode_block(b, bitmap + h * XFACE_WIDTH, w, h, level); + decode_block(b, bitmap + w + h * XFACE_WIDTH, w, h, level); + return; + } +} + +typedef struct XFaceContext { + uint8_t bitmap[XFACE_PIXELS]; ///< image used internally for decoding +} XFaceContext; + +static av_cold int xface_decode_init(AVCodecContext *avctx) +{ + if (avctx->width || avctx->height) { + if (avctx->width != XFACE_WIDTH || avctx->height != XFACE_HEIGHT) { + av_log(avctx, AV_LOG_ERROR, + "Size value %dx%d not supported, only accepts a size of %dx%d\n", + avctx->width, avctx->height, XFACE_WIDTH, XFACE_HEIGHT); + return AVERROR(EINVAL); + } + } + + avctx->width = XFACE_WIDTH; + avctx->height = XFACE_HEIGHT; + avctx->pix_fmt = AV_PIX_FMT_MONOWHITE; + + return 0; +} + +static int xface_decode_frame(AVCodecContext *avctx, + void *data, int *got_frame, + AVPacket *avpkt) +{ + XFaceContext *xface = avctx->priv_data; + int ret, i, j, k; + uint8_t byte; + BigInt b = {0}; + char *buf; + int64_t c; + AVFrame *frame = data; + + if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) + return ret; + + for (i = 0, k = 0; i < avpkt->size && avpkt->data[i]; i++) { + c = avpkt->data[i]; + + /* ignore invalid digits */ + if (c < XFACE_FIRST_PRINT || c > XFACE_LAST_PRINT) + continue; + + if (++k > XFACE_MAX_DIGITS) { + av_log(avctx, AV_LOG_WARNING, + "Buffer is longer than expected, truncating at byte %d\n", i); + break; + } + ff_big_mul(&b, XFACE_PRINTS); + ff_big_add(&b, c - XFACE_FIRST_PRINT); + } + + /* decode image and put it in bitmap */ + memset(xface->bitmap, 0, XFACE_PIXELS); + buf = xface->bitmap; + decode_block(&b, buf, 16, 16, 0); + decode_block(&b, buf + 16, 16, 16, 0); + decode_block(&b, buf + 32, 16, 16, 0); + decode_block(&b, buf + XFACE_WIDTH * 16, 16, 16, 0); + decode_block(&b, buf + XFACE_WIDTH * 16 + 16, 16, 16, 0); + decode_block(&b, buf + XFACE_WIDTH * 16 + 32, 16, 16, 0); + decode_block(&b, buf + XFACE_WIDTH * 32 , 16, 16, 0); + decode_block(&b, buf + XFACE_WIDTH * 32 + 16, 16, 16, 0); + decode_block(&b, buf + XFACE_WIDTH * 32 + 32, 16, 16, 0); + + ff_xface_generate_face(xface->bitmap, xface->bitmap); + + /* convert image from 1=black 0=white bitmap to MONOWHITE */ + buf = frame->data[0]; + for (i = 0, j = 0, k = 0, byte = 0; i < XFACE_PIXELS; i++) { + byte += xface->bitmap[i]; + if (k == 7) { + buf[j++] = byte; + byte = k = 0; + } else { + k++; + byte <<= 1; + } + if (j == XFACE_WIDTH/8) { + j = 0; + buf += frame->linesize[0]; + } + } + + *got_frame = 1; + + return avpkt->size; +} + +AVCodec ff_xface_decoder = { + .name = "xface", + .long_name = NULL_IF_CONFIG_SMALL("X-face image"), + .type = AVMEDIA_TYPE_VIDEO, + .id = AV_CODEC_ID_XFACE, + .priv_data_size = sizeof(XFaceContext), + .init = xface_decode_init, + .decode = xface_decode_frame, + .pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_MONOWHITE, AV_PIX_FMT_NONE }, +}; |
